Employees were unplugging a slurry strainer that was plugged with corn mash. They shut the slurry strainer down and took it offline to be cleaned and unplugged. When the machine was cleaned and put back online, a drain valve was not closed. Pressure forced the hose/pipes into the air, spraying hot liquid onto the employees. One of the employees suffered second degree burns on his neck, ears, and back, requiring hospitalization. The second employee suffered first degree burns on his cheek and ears, but was not hospitalized.